History of Science - 8
History of Science - 8.
Pieter Van Musschenbroek - (1692 - 1761).
Stephen Gray - (1670 - 1736).
Charles Du Fay - (1698 - 1739).
Benjamin Franklin - (1706 - 1790).
John Michell - (1724 - 1793).
Charles Coulomb - (1736 - 1806).
Luigi Galvani - (1737 - 1798).
Alessandro Volta - (1745 - 1827).
Daniel Bernoulli - (1700 - 1782).
Pierre Louis de Maupertuis - (1698 - 1759).
Leonhard Euler - (1707 - 1783).
Mikhail Vasllevich Lomonosov - (1711 - 1765).
Thomas Wright - (1711 - 1786).
William Herschel - ( 1738 - 1822).
Caroline Herschel - (1750 - 1848).
Jean d’Alembert - (1717 - 1783).
Pierre Simon Laplace - (1749 - 1827).
Benjamin Thompson- (1753 - 1814).
Scot James Hutton - (1726 - 1797).
It was a decade after Newton’s death, that the term physics came into use,
rather than the earlier ’Natural philosophy’.
It was actually a revival of an old terminology, since the word was used by Aristotle.
The first book with this name was published in 1737, by Pieter Van Musschenbroek.
It was the time that physicists were trying to understand the mysterious phenomena of electricity.
Pieter invented a device which could store large quantities of electricity.
It was simply a glass vessel coated with metal from the inside and outside.
It was an early form of what we now call as a capacitor.
This Leiden jar could be charged up for storing electricity.
If several of them were wired together they could produce a large discharge,
sufficient to kill an animal.
Stephen Gray published the article, in which he described,
how a cork in the end of a glass tube became charged when the glass was rubbed.
A pine stick stuck in the cork, could carry the electricity to the end of the stick.
Gray used glass spheres which was rotated while being rubbed, to generate electricity.
Charles Du Fay discovered two kinds of electricity in 1730’s.
We now call them positive and negative charge.
Fay discovered that similar kinds repel one another, while opposite kinds attract each other.
Fay demonstrated that anything could be charged if it was insulated.
He even electrified a man, and was able to draw sparks from his body.
He came up with a model of electricity comprising of two different fluids.
This model was refuted by Benjamin Franklin.
Franklin conducted the famous kite experiment in 1752,
to prove the connection between lightning and electricity.
He carried out many experiments, and came up with a model that electricity is a single fluid.
He came up with a concept of negative charge and positive charge.
Charge is conserved, but it can be moved around.
He showed that electricity can magnetise and demagnetise iron needles.
Earlier John Michell, a friend of Henry Cavendish, devised the Cavendish experiment.
In 1750, Michell discovered that the force of repulsion between two like magnetic poles,
obey the inverse square law.
At that time nobody took much notice of the various contributions of Franklin, Priestley and Cavendish,
in establishing that electric force obeys an inverse square law.
In 1780, Charles Coulomb carried out definitive experiments,
which established that magnetic and electrical forces obey the inverse square law.
It is now known as Coulomb’s law.
This is one more example which highlights the interplay between science and technology.
The inverse square law was finally established using the technology of a torsion balance.
Luigi Galvani, professor of obstetrics carried out experiments in animal electricity.
He noticed a twitching in the muscle of a frog, in dissection.
He carried out many experiments and concluded that the twitching,
was caused by electricity in the muscles of the frog.
Not everyone agreed with him, in particular Alessandro Volta, in Lombardy, Italy.
Volta proposed that the stimulus for the contraction of the muscles came from an outside source.
Volta tested his ideas, by placing different metals in contact and touching them with his tongue,
which was sensitive to tiny electrical currents, which could not be detected with instruments.
He came up with a device to amplify this signal in 1799.
His key invention was a pile of silver and zinc discs separated by cardboard discs,
soaked in brine.
It was known as the voltaic pile, and was the forerunner of the modern battery.
It provided more or less a steady flow of current.
Before Volta’s invention the study of electricity was confined to static electricity.
After Volta’s invention, physicists could work with electric currents.
They could increase or decrease the current.
Other researchers found that this current could split water into hydrogen and oxygen.
Volta’s battery became a powerful tool for science.
When Napoleon won control of Lombardy in 1800, he made Volta a count.
Daniel Bernoulli published a book in 1738, on hydrodynamics which described the behaviour,
of liquids and gases, in terms of the impact of atoms, on the walls of their container.
This was similar to the kinetic theory of gases developed later.
In 1743, Benjamin Franklin established the first scientific society in the U.S.,
the American philosophical society in Philadelphia.
Pierre Louis de Maupertuis published the principle of least action in 1744.
’Action’ is the property of a body, measured in terms of changing position of an object and its momentum.
The principle of least action says, that nature always keeps this quantity to a minimum.
This turned out to be extremely important in quantum mechanics.
The simplest example of this principle is that light always travels in straight lines.
Leonhard Euler was a prolific Swiss mathematician.
He introduced the mathematical notations of ‘e and i’.
He described mathematically the refraction of light, by assuming the light is a wave,
with each colour corresponding to a different wave length.
This model languished because it did not conform to Newton’s ideas.
Mikhail Vasllevich Lomonosov came up with a kinetic theory similar to that of Bernoulli in 1748.
But his work was virtually unknown outside Russia during his life time.
Many such ideas were ahead of their time.
Thomas Wright published a book suggesting that the sun is part of a disc of stars like a milk wheel,
which we now call the milky way.
In 1781, William and Caroline Herschel discovered the planet Uranus.
It was a sensation at that time, because it was the first planet that was not known to the ancient Greeks.
John Michell was the first person to come up with an idea, now known as black holes.
It was known at that time that light has a finite speed.
The more massive an object is, the faster we have to move to escape from its gravitational grip.
Gravity is so strong that light cannot escape from a black hole.
This is how astronomers infer the existence of black holes today.
Pierre Simon Laplace came at the similar idea independently.
Laplace was born in 1749 in Normandy.
His initial studies was probably intended to make him a priest.
While at college he was found to have a talent for mathematics.
Laplace went to Paris with a letter of introduction to Jean d’Alembert, a top mathematician,
who appointed him as a mathematic professor in a military college.
He wrote several papers, and was elected to the academy in 1773.
Laplace was particularly interested in probability.
All the planets move around the sun in the same direction, and in the same ecliptic plane.
But comet’s orbit the sun in all directions, and at all angles.
This suggest that they have a different origin, as already known to earlier mathematicians.
Laplace developed a more sophisticated analysis to study their motion.
He studied the orbits of Jupiter and Saturn.
These orbits showed a slight long term shift, which did not fit in with Newton’s gravitational theory.
Newton himself had suggested that divine intervention would be required,
to put the planets back into proper orbit, and prevent the solar system from falling apart.
Laplace was able to explain within the framework of Newtonian theory, that the cause of the shift,
was the disturbing influence of the two planets.
The variation have a 929 year cycle, which brings it back to where it started.
Divine intervention was not required after all.
He developed his ideas on probability, to deal with practical problems,
such as estimating the total population of France from a sample of birth statistics.
He worked with Lavoisier on the study of heat.
They discussed the old caloric model of heat, and the new kinetic theory.
They suggested that both could be at work at the same time.
Laplace had already worked on the metric system.
He reformed the French education system, to include the teaching of science.
He published an influential book about science, ‘Exposition’ in 1796.
He served in the government under Napoleon, who made him a Count in 1806.
When the monarchy was restored, Louis XVIII, made him the Marquis de Laplace.
His book Exposition, which summed up, where physics stood at the end of the 18th century,
was his most important contribution.
His book covered a variety of subjects.
One of his ideas was the nebular hypothesis, that planets formed from a cloud of material around the sun.
This model is still in use today.
He also introduced his idea about what we now call as black holes.
He calculated that a body with a diameter 250 times of the sun, and the density of the Earth,
would have such a strong gravitational attraction, that even light could not escape from it.
Benjamin Thompson made important contributions to science particularly in the study of heat.
His family was poor, and they could give him only a rudimentary education.
At the age of 13 he had to work to support his family.
He became an apprentice to a physician Dr. John Hay.
In order to pay his way, Thompson took a variety of part time teaching jobs.
Sarah Walker was married at the age of 30 to the richest man in town.
Her husband died early, leaving her very well off.
In 1772, Thompson married Sarah Walker.
He turned into a gentleman, and settle down to manage his wife’s estate.
He was only 19, tall and good looking.
They had 1 child, Sally.
Thompson was never satisfied with what he had, and always wanted something more.
It was the time of the American revolution.
Thompson favoured the ruling authorities
Thompson was appointed as a major, in the new Hampshire militia, in 1773.
The colonials, plotting to overthrow the old regime were aware of his activities.
In 1774, a mob gathered with the objective of tarring him.
Thompson headed out of town on horseback never to return.
He never saw his wife again.
He became a spy for the British authorities, passing information about rebel activities,
to the head quarters in Boston.
When the British were thrown out by the rebels, in 1776, the loyalists sailed to Nova Scotia.
He then went to London as an expert with information on the fighting abilities of the American rebels.
He became the right hand man of Lord George, the secretary of state for the colonies.
By 1780, he became the under-secretary for the northern department.
Along with that work, he also returned to scientific interest.
He carried out experiments to measure the explosive force of gunpowder.
He was elected as a fellow of the royal society 1779.
He became a spy for Lord George, and reported the inefficiency and corruption in the Navy.
He formed his own regiment, and became the lieutenant colonel, in the king’s American dragoons.
In 1781, a French spy was caught with the details of the British naval operations.
Thompson was suspected, but not charged.
He left for New York to fight for his regiment.
After the defeat of the British in 1783, he was back in London.
He was promoted as a full colonel.
After retirement he became a military aide, in Munich by the elector of Bavaria, Carl Theodor.
He had to return to London to get the king’s permission to serve in a foreign power.
Thompson persuaded the king to give him knighthood, which was duly granted.
Sir Benjamin Thompson offered to spy on the Bavarians for the British.
Thompson was a phenomenal success in Bavaria.
He applied scientific principles to build an efficient army.
Thompson studied the way heat was transmitted, to find a cost effective material for their uniforms.
He accidentally discovered convection currents.
He studied nutrition and worked out how to feed the soldiers economically but healthily.
Among his many inventions, Thompson designed the first enclosed kitchen ranges,
replacing inefficient open fires.
He invented portable stoves, improved lamps and efficient coffee pots.
He soon became the minister of war.
At that time the last vestiges of the holy roman empire still existed.
It was a loose coalition of European states, with a ceremonial emperor.
When emperor Leopold died, Carl Theodor became the holy roman emperor, as a care taker.
Sir Thompson now became a Count Rumford, when he was 39 years old.
Out of the blue, he received a letter from his daughter, Sally.
When war was threatening to engulf Bavaria, Thompson left for Italy.
He revived his interest in science.
He saw Volta demonstrating the twitching of frog’s legs, under the influence of electricity.
He returned to Bavaria in 1794, to make a name for himself in science.
To get his work published by the royal society, he went to London.
He designed a better fire place, which prevented smoke from coming into the room.
He brought Sally over from America to join him.
Though he was initially embarrassed by her country bumpkin ways,
they settled down and spent a lot of time with each other.
Thompson was appointed as an ambassador to Britain.
King George III did not accept his credentials, since he was a British national.
Thompson established a museum for research and education, which became the Royal institution in 1800.
The Royal institution became a huge success in promoting public understanding of science.
He met the widow madame Lavoisier in 1804, and decided to marry her.
There was a technical difficulty, since he had to prove, that his first wife was dead.
They lived together and eventually married in 1805.
Then they discovered that they were not compatible.
Thompson wanted a semi retired life, doing scientific work.
His wife wanted parties and a full social life.
They parted ways, and Thompson lived with another mistress.
Thompson died in 1814.
Thompson made an important contribution to our understanding of the nature of heat.
At that time, every body was thought to possess caloric.
When caloric flowed out, it raised the temperature.
While in Munich, Thompson noticed that a cannon became hotter,
if it was fired without a cannon ball, even though the same amount of gunpowder was used.
He also noticed that when a cannon is drilled using horses, it produced heat.
He demonstrated that this heat could make water boil.
The fact that water could be made to boil without fire fascinated people.
He established the fact that there is no connection between the amount of heat in a body, and its mass.
He understood that nothing could be flowing in and out of the body, when it was heated or cooled.
This helped later scientists to discard the caloric model of heat.
In terms of understanding the place of humankind in space and time,
was the understanding of geological processes that shaped the Earth.
The first version of this story, was put together by Scot James Hutton.
James was born in a modest form in 1726, in Edinburgh.
He was apprenticed to a lawyer at the age of 17.
He showed no aptitude for law, and was deeply interested in chemistry.
He went to the university to study medicine, which was the nearest thing to chemistry at that time.
He received his M.D. in 1749, but never practiced medicine.
He worked on improving the farm that he had inherited.
While doing this, he developed an interest in geology.
Along with a friend, he invented a process for manufacturing ammonium chloride,
which was used for preparing cotton for dyeing and printing.
With the money coming from this, he decided to devote himself to science, at the age of 42.
He was a friend of Joseph Black.
He was the founder member of the Royal Society of Edinburgh, established in 1783.
He is best known for suggesting that the Earth is much older than what theologians said.
He proposed that given time, mountains could be worn away by erosion,
the sediments being laid down on the sea floor, and later uplifted to form new mountains,
by earthquakes and volcanoes.
This became known as the principal of uniformitarianism.
He published his work in 1788.
His work was criticised by other scientists.
He defended his ideas in the book, ‘The theory of the Earth’, published in 1795.
He died in 1797.
James pointed out that the natural processes of the Earth should certainly take more than 6000 years,
as interpreted.
He said the age of the Earth is beyond comprehension.
He was continued to be criticised after his death.
His friend John Playfair, wrote a masterly summary of James Hutton’s work, in 1802.
This reached a wider audience, who realised that James’s ideas had to be taken seriously.
But it took another generation for the seed planted by James, on uniformitarianism, to flower.